Guest driven rearrangements of protonation and hydrogen bonding in decavanadate anions as their tetraalkylammonium salts

Single crystal X-ray structure determinations of (n-C5H11)4N]3H3V10O28].2(CH3)2CO (TAA-acetone), (n-C5H11)4N]8H3V10O28]2H4V10O28].7C4H8O2 (TAA-dioxane), (n-C5H11)4N]3H3V10O28] (TAAh) and (n-C6H13)4N]2H4V10O28].4C4H8O2 (THA-dioxane) revealed that protonation and hydrogen bond formation of decavanadate anions in their tetraalkylammonium salts are influenced by the nature of the solvent molecules incorporated as guests into the crystals. When crystallized with acetone molecules, the decavanadate anion forms a self-associated hydrogen-bonded dimer of (H3V10O28](3-))2 to hide the protons from the aprotic protophobic acetone molecules. When crystallized with 1,4-dioxane molecules, the decavanadate anion exposes its protons to the aprotic protophilic 1,4-dioxane molecules to form a hydrogen-bond assisted solvation complex of ((C4H8O2)4...H4V10O28)](2-)). Size effects of the tetraalkylammonium cations on crystallizing these hydrogen-bonded assemblies were also examined.